Starting Bubbles: 50
7 extra Bubbles, 3 extra holes in the ceiling
Points needed for 1, 2, 3 Star:
65 000, 80 000, 90 000
4 Bomb Bubbles
Doom Skull Bubbles
First you focus on stopping the Infection at level 84 as soon as possible. Then you take down the Bombs in order that they are, the lowest first, and the highest (fourth) one, you do not necessary need to get down before the ceiling break.
If you use the recommended Magic Potion for 3 extra holes in the ceiling, you might get surpriced, seeing the ceiling fall down all the sudden, before you even can see the holes in it!
Here is a great video walkthrough from skillgaming.de to model YOUR STRATEGY for level 84 a bit more fancy.
Here is an alternative video by candicvodka.